[ARM PATCH] 1293/1: fix to the ARM optimized strchr()

Two bugs here:

1) The return value of strchr("foo",0) should be the start address of
   "foo" + 3, not NULL.

2) Since the second argument for strchr() is defined as an int, some
   characters such as 'é' might validly end up to be the value -23 due to
   signedness issues.  Corectly handle those.

arch/arm/lib/strchr.S

@@ -15,11 +15,12 @@
 		.text
 		.align	5
 ENTRY(strchr)
+		and	r1, r1, #0xff
 1:		ldrb	r2, [r0], #1
 		teq	r2, r1
 		teqne	r2, #0
 		bne	1b
-		teq	r2, #0
-		moveq	r0, #0
-		subne	r0, r0, #1
+		teq	r2, r1
+		movne	r0, #0
+		subeq	r0, r0, #1
 		RETINSTR(mov,pc,lr)